Catholic Encyclopedia
St. Martina, Roman virgin and martyr, d. 226 or (more likely) 228.
For All the Saints
Gives 228 as the year of the saint's death, says that in 1969 her feast was removed from the general Roman calendar but not from local calendars.
Lives of the Saints
St. Martina, virgin, martyr. From Fr. Alban Butler's Lives of the Saints.